Abstract

MARTINS, Maria Augusta G.. Monitorização da degradação térmica do papel isolante usado em transformadores: Papel "Thermally Upgraded" Versus Papel Kraft. C.Tecn. Mat. [online]. 2007, vol.19, n.1-2, pp.14-18. ISSN 0870-8312.

Furfuraldheide (2FAL) concentration in oil, analysed by High Performance Liquid Chromatography (HPLC), has been successfully used, even with some limitations, as a diagnostic tool for the insulating Kraft paper thermal degradation monitoring, in transformers. This is not only because 2FAL is the furanic compound produced in major quantity, by Kraft paper degradation, but also because 2FAL has a good solubility and thermal stability in oil. However, 2FAL is not a so good indicator of Thermally upgraded insulating paper degradation, as it is, for Kraft paper degradation. This information is quite important, as the use of this type of paper in transformers is lately spreading out, more and more, mainly in the field of ultra high voltage transformers. The degradation phenomena of Thermally upgraded paper "Insuldur" are presented here, in order to explain, why 2FAL concentration in oil acts as a lower sensivity indicator, of Thermally upgraded paper degradation, than of Kraft paper degradation. The results of an experimental comparative study of thermal degradation, of these two types of paper, are also discussed here. It is quite probable that another furanic compound, like the furfurilic alchool (2FOL) can be used as a better indicator for the Thermally upgraded paper degradation. However, more research must be done, in order to confirm this hypothesis.

Keywords : Furfuraldheide; 2FAL; Thermally upgraded paper; Degradation; Insuldur; Transformer; Furfurilic alchool; 2FOL; Furanic compounds; Kraft paper.

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